A new age model for the Central Arctic reveals brief intervals of extreme sedimentation rates over the last 140 kyr

Abstract

A detailed age model for central Arctic sediments (Mendeleev Ridge) reveals remarkably high sedimentation rates of >20 cm kyr−1 during brief intervals during the last 140 kyr. This age model is developed using a modified event stratigraphy based on changes in source provenance, mineral, and geochemical variations that are correlated from a core with a detailed age model on the Yermak Plateau near Fram Strait (HLY0503-22JPC) to a core on the Mendeleev Ridge (HLY0503-9JPC). The Yermak core has a previously determined age model linked to the global δ18O ice volume record. The age model presented here indicates that the average sedimentation rate in core 9JPC is only ~2 cm kyr−1, but brief periods of intense sediment accumulation range up to >20 cm kyr−1. Many of these events are identified to be basin-wide and possibly associated with major freshwater or ice-rafting events indicating that these events are tied to climatic glacial/interglacial processes. During marine isotope Stage 3 for instance, an ice-rafted detritus event contemporaneous with Heinrich event 4 is identified and can be linked to a large-scale event by precise source determinations using the chemical fingerprint of detrital, ice-rafted Fe oxide grains. The provenance indicates that this event is contemporaneously sourced to three major regions of Arctic glaciation. There are other rapid sedimentation events that are not correlated to both cores and these must be from localized melt-out events from either icebergs or sea ice.